Basal bodies have been postulated to play a variety of roles in the cell. Among these possible roles are the placement and assembly of flagella, initiation of the cell cycle, formation of the mitotic spindle, animal cell migration patterns, and intracellular organization. These processes have pronounced medical significance. We propose to analyse mutants in Chlamydomonas reinhardtii that affect basal bodies. The aim is to understand the spectrum of phenotypes that basal body mutations can display and to begin to understand the steps in the morphogenesis of this organelle. Further mutations that affect basal bodies will be isolated. We will isolate new alleles of previously identified loci by screening heterozygous mutant/wild-type diploid cells for the appearance of the mutant phenotype and we will identify new loci by isolating extragenic suppressors of existing loci by screening haploid mutant cells for the wild-type phenotype. We will characterize the new mutants by phenotypic analysis at a variety of temperatures, by genetic analysis, by biochemical analysis of preparations enriched in basal bodies, and by electron microscopy. We will try to improve the presently available transformation system in Chlamydomonas using homologous genes from Saccharomyces. We wish to identify the genes that affect basal bodies by complementation using recombinant DNA. The cloned genes will be used to identify the gene products by in vitro translation of hybrid selected RNA.